pcmanfm can navigate to computers running sshd using sftp under LXDE (requires gvfs to be added to base Sabayon LXDE install). If I change the WM from open-box to icewm or switch to plain icewm, sftp stops working in pcmanfm.

The cause of the problem is in this file:

/etc/lxdm/Xsession

They have custom xsession launchers for fedora, mandriva, debian, and ubuntu all other distros are classified as unknown and the script suggests that you create a custom xinitrc file here:

/etc/lxdm/xinitrc

If that file doesn't exist (the default) it runs a generic launcher which does not launch dbus-launch which is why pcmanfm can't do sftp with icewm. I found a solution: